1. Field of Invention
This invention relates to a method and system for electricity generation, and more particularly to a modular system of traffic supporting roadway panels for collecting solar energy, converting the solar energy into grid-ready electricity, and distributing the electrical energy.
2. Background and Description of Prior Art
It is well know that electricity may be derived from photovoltaic systems made of solar panels formed from silicone and the like that collect solar energy. A plurality of solar panels is generally referred to as a solar “array” which, by definition is larger than a solar panel, and correspondently has an ability to collect more solar energy and generate more electrical energy.
Solar energy is generally harnessed in two ways. Thermal solar energy typically uses dark colored surfaces to collect heat from sunlight, and then transfers the heat energy, via liquids, to a location where it can be used. This system is common in heating swimming pools. The second method uses photovoltaic cells that employ semi-conductor materials that translate photon energy within sunlight to direct current (DC) electrical energy.
A typical solar energy cell is solid state device in which a junction is formed between adjacent layers of semi-conductor materials. When photons strike the semi-conductor, electrons are dislodged. These dislodged electrons, which are collected by the electric field at the junction, create a voltage that can be put to work in an external circuit. The basic scientific principals that underlie generation of electricity using solar cells are well-known and understood to those skilled in the art.
Solar power generation is one method of generating clean energy. However, even though the cost of solar power systems has decreased in recent years, while at the same time the efficiency of such systems has improved, there remains a lack of a cohesive integrated infrastructure that uses solar energy as a power source.
Instead, solar energy is typically employed in small scale isolated instances. This lack of a cohesive infrastructure is one contributing factor to the fact that presently, solar power is estimated to generate less than approximately five percent (5%) of the energy consumed in the United States.
Further, it is known to use inverters and the like to add excess electricity generated by solar arrays back into a community's electrical grid.
However, there are also problems associated with solar arrays that are found mostly in roof based installations. Individually mounted solar panels on roofs are relatively expensive and such panels are often unsightly. Further, many times there is limited space on a rooftop for installation of an effective array. More fundamentally, however, individual systems for individual houses and structures, as well as installing the associated infrastructure, is inefficient and costly. Many areas of high electricity use have limited roof space and have limited unused ground space in which the relatively large solar arrays may be installed. Thus, the limited available space on buildings and many urban and suburban areas for placement of panels generally would not generate sufficient electricity to make such a system economically viable.
Further, some residential, commercial, community and governmental customers find the appearance of such solar panels on roofs unappealing and unattractive. In some locals, local regulations and covenants may prohibit installation of such panels.
Finally, selling and installation of solar panels to individual commercial and residential customers is inefficient, and adoption in the United States has been slow. Solar farms, which are land based operations, have increased the use of solar energy, but do not offer many of the advantages that could come from a widely distributed generation array. Further current solar arrays are typically centralized in one location making such arrays vulnerable to disruption.
What is needed is a widely distributed solar panel array that uses existing supportive surfaces that can be used for things other than only collection of energy.
Our invention resolves several of the aforementioned disadvantages of known solar arrays, and provides a system for the efficient collection of solar energy, transformation into electrical energy and distribution thereof.
In the contiguous lower 48 states, there are approximately 25,000 square miles of supportive surfaces including roads, parking lots, driveways, sidewalks and the like, not including buildings and structures. Our invention replaces current methods of building roads, parking lots and driveways, and the like, with a means for accomplishing the same end result, but with an incorporated system that collects solar energy and generates electric energy for distribution to homes, businesses, and the electrical grid throughout the nation. In short, current roadways, parking lots, and driveways are replaced by, or covered with solar panels that may be driven upon by vehicles while simultaneously generating electricity for useful purposes.
Our system is comprised of a plurality of interconnected and networked solar road panels. Each panel is comprised of three vertically adjacent layers including an upper surface layer, a middle layer, and a lower base. Each solar road panel is able to withstand various weather conditions including expansion and contraction due to thermal variations.
The upper surface layer is driven upon by a vehicle and provides good traction under various weather conditions. The upper surface maybe heated by internal heating means in cold climates to prevent ice and snow accumulation. The upper surface layer is constructed of a material that passes light to photovoltaic cells while providing sufficient strength and integrity to support vehicular and pedestrian traffic thereon.
The middle layer carries control structure that contains the electronics of the solar road panel including necessary circuitry, cabling, interconnection plates and the like.
The lower base supports both the control structure and the surface layer. The base may rest directly upon the ground surface, an existing supportive surface, or may be supported by vertical risers.
The solar roadway panels are interconnected electronically to allow electricity collected by the photovoltaic cells within a solar panel to be stored and distributed as desired. It is further envisioned that the solar road panels may be used to distribute other types of electric signals including cable TV, Internet connections, telephone information and the like.
The panels may be illuminated using embedded light emitting diodes (LED's). Illumination of selected LED's allows the user to “paint” lines and information on the roadway at desired locations by activating and deactivating selected LED's as desired for instance to widen, narrow or re-route traffic lanes as well as for displaying words such as “SLOW DOWN”, “CAUTION”, “DETOUR” and the like on the panels.
Each solar roadway panel contains a controller 28 with a unique identification code. Because the solar roadway panels are networked with one another and with the power and signal distribution grid, the controllers 28 may also be networked together.
During daylight hours the photovoltaic cells convert sunlight energy striking the panels into electrical energy, and store the electrical energy in large value capacitors, batteries or other known electricity storage devices as desired. The stored energy may thereafter be used to illuminate the LED's contained within the panel, or to heat the panel to prevent accumulation of snow and ice thereon, or the energy may be sent for distribution to a power grid.
A nationwide network of such solar roadway panels would, for example, allow the west coast to supply electricity to the east coast for several hours after the sun goes down on the east coast. Likewise, the east coast could theoretically generate electricity for the west coast for the first three hours of each day when the sun has risen in the east but has not done so in the west.
Research has shown that commercially available photovoltaic cells have approximately 15% efficiency; the US averages about 4 hours of peak sunlight hours per day (1460 hours per year); and one square mile of Solar Roadways would generate approximately 37.76 Mega-Watts of electricity per year.
If the approximately 25,000 square miles of roadway surfaces were replaced with Solar Road Panels, over 13,417 billion Kilowatt-hours of electricity could be generated per year.
According to the Energy Information Administration, the United States consumed just over 4,372 billion Kilowatt-hours of electricity in 2003, while the entire world (including the U.S.) used approximately 14,768 billion Kilowatt-hours of electricity total. Our system is capable of producing more than three times the total electricity usage of the entire United States.